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Surge protectors-why is it restricting sound?

Philim

pfm Member
I am running a Naim XS off a surge protector and have noticed what I can only describe as a wave of sound quality - sometimes OK; sometimes muffled. Having seen a few threads saying "all Naim equipment must be run from a wall socket" I tried running straight from a £4 basic extension lead and the difference is quite noticeable. Linear performance, more detail and separation but a little brighter.

WHY? WHY? WHY?

On the flipside I might paint my £4 extension lead black and sell for £250 on the Naim forum.....
 
because the surge protector increases the impedance of your mains supply and probably inject HF noise into the bargain, or you've imagined it.
 
Phil,

An email to [email protected] will get you an accurate answer if not the same as Simon suggested with minimizing mains supply impedance (the prevailing theory.)

FWIW, I run my Naim rig here without extension cords or mains blocks for the same reason - it sounds better that way.

regards,

dave
 
Naim recommend star earthing so things like the grahams hydra are a good option. I used one for my 202/200 hicap/napsc system and whilst i didn't notice much of a change i was able to power it all from a single wall socket.
 
Surge protectors have a number of components that reputedly spoil SQ
X & Y capacitors (IME) soften SQ
Varistors (VDR or MOV) the avctual surge protector, although normally set to operate above the nominal voltage, they tend to rim the top end of te wave peak

Finally what are do you think you are protecting against ???
These devises will simply vaporize with the potential of a lightening strike - the only protection for lightening is a good insurance policy
UK power is as good as anywhere on the planet & high voltage surges as found in 3rd world places that could damage equipment do not happen.
 
Surge protectors have a number of components that reputedly spoil SQ
... they tend to rim the top end of te wave peak
I'm sure you have strong feelings on this subject but there's no call for that kind of language.
 
How can anything before the amplifier mains affect sound quality, the signal is regulated to dc and if the psu is done well enough it will compensate for whatever voltage droops/rises there may be.

Please explain.
 
Not all amps are built equal, PSRR varies with design, harmonics on the mains make their way through, DC on the mains causes the transformer core to saturate, lowering it's ability to do it's job.
 
How can anything before the amplifier mains affect sound quality, the signal is regulated to dc and if the psu is done well enough it will compensate for whatever voltage droops/rises there may be.
Please explain.

2 answers in my experience

I hear what I hear & I have heard a so called surge protector that included VDR, X&Y caps & C&D mode chokes that softened the sound on my old Audiolab system a few years ago, then when I dug it out & used it with my Naim, it did the same.

Years ago I managed a project to develop a prototype command vehicle that was required to have very low electrical noise.
They had to run off both mains power & a number of different mobile generators. In an effort to suppress electrical noise from the generators we designed in stuff that included capacitors on the power input. It resulted in downstream issues with low voltage & 24vDC regulation. Problem was the waveform was distorted so it was no longer a pure sinusoidal form, the transformer current draw & its AC output was affected. We removed most all the capacitance & the problem was solved

How that might transpose into the SQ of an amp, I am not sure & not claiming it does.
Maybe some of our DIY builders can add something
 
It's a big horrible mess. Bits added there interact with everything upstream and down, all the strays along the way (wiring and transformer leakage inductances and so forth) so its very difficult to make blanket recommendations. Or even recommendations at all other than leave well alone unless you're sure your power is so bad you need remedial measures.

I've experimented quite a bit with filtering design. Take just one element -adding varying amounts of capacitance across the line at the input to amps*. It's quite easy to provoke more and peakier noise within the audio band measured at the AC power input to the amp than without. Again, this may or may not manifest itself as measurable (let alone audible) outcomes on the audio output, depending on the object powered.


* Exactly as often sold as a 'parallel filter' or some such nonsense.
 
Has someone tried large isolation transformers from Torus or Bryston? They provide a lower source impedance and don't seem to have caps.
 
It's still higher impedance than the raw mains, plus a small amount of leakage inductance. (in the UK Airlink among others can also supply high quality units up to 'enormous' )

I've got a largish (well, 1.5KVA continuous rated, about 20kG) isolation transformer and even so teh few times I've played with it on the system it gave a flattening effect on dynamics was noticable even with a load as weedy as a Nait2. Not sure why, nor much pursaded to investigate. I only use it when I need isolation i.e. on the bench.
 
It's still higher impedance than the raw mains, plus a small amount of leakage inductance. (in the UK Airlink among others can also supply high quality units up to 'enormous' )

I've got a largish (well, 1.5KVA continuous rated, about 20kG) isolation transformer and even so teh few times I've played with it on the system it gave a flattening effect on dynamics was noticable even with a load as weedy as a Nait2. Not sure why, nor much pursaded to investigate. I only use it when I need isolation i.e. on the bench.

Bryston's brochure says a standard wall receptable have a higher nominal impedance.
"
BIT power isolation units present low impedance to any electronic
device that is connected to them. A Single 20 amp BIT PIU has
an output impedance of 0.2 ohms and can deliver 400 amp peaks
(instantaneous current). The 100 amp unit only has .04 Ohms
of output impedance. A typical 200 watt audio power amplifier
demands 10 amps RMS current from a 120 volt line (1200VA)
but may demand up to 50 amp instantaneous peaks. The standard
residential wall receptacle can’t supply the 50 amp peaks because
they typically have higher nominal impedance. A BIT 20 amp
PIU plugged into the same wall plug can supply these peak current
requirements quite easily
."

http://bryston.com/PDF/brochures/BIT_BROCHURE.pdf
 
Looks like its using the Plitron narrow-bandwidth transformer.

But still, that press release makes no sense. That energy has to come from the wall socket, and it's not a step-down transformer. The transformer itself may have a lower wire resistance than the mains that feeds it but that alone does nothing.
 
Most of the RFI filters I have seen use a couple of Y caps connected from Live and Neutral to earth. These filters are no good for audio use.
 


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